The rise of popularity of free online scan services urged programmers to make web scanners as friendly as possible. In fact every such scanner is very easy to use because all it requires if just several mouse clicks.
The marketing war stands behind proprietary inventions and patented algorithms - normally the online virus scan is operated by the same engine as a stand-alone antivirus product. Each company tries to implement some peculiar feature to differentiate its product from competitors. So such figures as detection rate and scanning time, ability to remove found infections, option to scan for spyware and rootkits, smaller signature database size, user-friendly scan progress window to a great extent increase the likelihood to become popular among end-users.
However, we should always remember that online virus scan differs a lot from any desktop version of the product. It certainly has its advantages, but there are negative points as well. Pros and cons of online scanning services are listed below.
So, what can we consider to be strong points of just about every online antivirus?
1. They are all free.
2. Whenever you initiate such scanner you may rest assured it will be using the latest database of virus threats compiled by the security labs of the vendor.
3. Wide choice of virus scanners. While you often can't install two or more different antivirus solutions on a Windows desktop, when it comes to online scan you may choose the one you like - no limits here. So you may switch between several scanners whenever you need to.
4. Sometimes it happens that the installed anti-virus software is corrupted by malware, so you can't use the stand-alone product. You can't reinstall or repair it because smart virus makers foresee such actions on your part and corrupt Windows installation routine as well. In such case online virus scan often is not just the easiest, but the only escape you are left with.
5. No additional files are put into Windows registry and system folders, so the system configuration is not changed.
6. Online scan is a good way to test the security of the PC and verify its protection.
But there are serious drawbacks typical for online scanners, and you should be aware of them.
1. Of course everything starts with a stable Internet connection. Without it you can't use online services.
2. Proactive defense is a feature of stand-alone PC security products only. Online virus scan cannot serve as a security shield. It simply finds the threats and removes them, if possible. When the scan has been finished, there's no guarantee your PC won't get infected the next minute.
3. Sometimes a virus living inside the PC can prevent the online scanner from downloading its database files onto hard drive.
4. The types of malware detected by online scan are usually much less than those found by stand-alone full-features antivirus product.
5. Most online scanners require Internet Explorer with ActiveX enabled.
All that said, I highly recommend to use some online scanner from time to time, just to be on the safe side. It can complement the installed antivirus solution, and test the security shield. It's free, after all.